Subscribers to paging communication services continually demand increasingly powerful and sophisticated features. However, this demand conflicts with an equally important requirements of minimized size and increased battery life. Contemporary state-of-the-art pagers are designed so as to minimize their physical size. Therefore, it becomes difficult to incorporate advanced features into contemporary pagers since these feature typically require control or activation by the subscriber, and the size of the pager renders the addition of control switches or keypads impractical.
Voice recognition technology has been recognized as an advantageous feature for many product applications. Such technology may be employed to render a product partially or entirely controllable by voice commands in situations where hands-on control is impossible or impracticable. Speaker dependent voice recognition devices are designed to respond to a particular individual. Stored within such devices are speaker specific parameters, such as, for example, variations in the vocal tract response, pitch period, short-term speech power, and amplitude of the short-term speech spectra.
When applied to paging communication systems, voice recognition raises several concerns. One such concern involves the problem of storing the voice recognition information (commonly referred to as a "codebook") in the pager. Presently, pagers are typically provided with subscriber specific information, such as, for example, an identification code. However, this type of information may be readily generated and stored within the pager. Thus, if a pager should fail, a service company may easily supply the subscriber with a replacement pager. However, the generation and transference of a voice recognition codebook may not be as fundamental as identification code transfer.
In some circumstances, it may be desirable to enable a single pager to respond to the voice commands of more than one individual (subscriber). A typical situation may be in a company setting wherein a pager is temporarily provided to an individual that must be available to respond to some emergency or important situation. In another situation, a single pager may be shared between, for example, maintenance personnel operating in working shifts (i.e., three eight-hour shifts). Therefore, to provide voice control, the codebook for each individual must be stored within the pager. However, mass codebook storage may significantly increase the cost of the pagers. Additionally, codebook maintenance costs would be significant since the pagers must be updated with each change in personnel. Moreover, the addition of several memory devices, or a memory printed circuit board, may increase the size of the pager beyond that desired by the consuming public. This is a particular concern of paging subscribers. An alternative may be to use speaker independent technology, however, speaker independent devices are typically more complex, less accurate, and require more batter energy.
One solution may be to store the codebooks of only a few individuals thereby reducing the amount of required memory. However, this approach is inflexible to changing circumstances such as variations in personnel working hours or in the event that the pager itself should fail. Another approach may be to have each pager contain only enough memory for a single codebook, which must be retrained for each subscriber. Speaker dependent voice recognition devices must be "trained" to respond to each individual. Training is accomplished by having an individual repeat control words several times until the device has been "trained" to recognize that word as spoken by that individual. However, training is a time consuming process and the addition cf circuitry to provide training capabilities in each pager may adversely impact pager cost and size. Accordingly, a need exists in the art to permit pagers to be programmed to respond to the voice commands of subscribers in an efficient and organized manner.